Separation Of Photoinduced Charge Carriers Research Articles

Fabrication of two-dimensional FePS3 nanosheets for promising photo/electrocatalytic applications

Transition metal phosphorus trisulfides, namely sulfides composed of three elements, stand out within 2D nanomaterials due to the unique layered structure, distinctive bonding, and electronic configurations. However, the preparation of ultrathin nanosheets encounters significant challenges due to the inherent properties of the material itself and the complexity of the synthetic process. In this work, we successfully fabricated ultrathin FePS3 nanoflakes with lateral dimensions of 500-800 nm and an average thickness of 5 nm utilizing mechanically assisted liquid-phase exfoliation in N-Methyl-2-pyrrolidone solution. The unique few-layer structure of FePS3 may increase the number of active sites, facilitating the rapid separation and migration of photo-induced charge carriers. Consequently, this enhancement leads to an increase in photogenerated current and a substantial reduction in resistance. This study presents an effective approach for optimizing light absorption and charge separation processes of 2D nanostructure, thereby providing valuable insights for the rational design of efficient photocatalysts based on ultrathin FePS3 nanosheet as a co-catalyst.

Co–N–C anchored g-C3N4 plate enhancing surface activity for efficient visible-light photocatalytic rhodamine-B elimination and CO2 conversion

Poor light-harvesting, fast recombination of photo-induced charge carriers, and unfavorable surface adsorption remain the major issues restricting the photocatalytic activity of g-C3N4. In this study, the Co-N-C decorated g-C3N4 (Co-N-C/g-CN) plate was developed by constructing Co-N-C on the surface of g-CN plate to improve photocatalytic rhodamine-B (RhB) degradation and CO2 conversion. The as-prepared 0.5Co-N-C/g-CN plate exhibited an exceptionally high efficiency in photocatalytic RhB degradation, with a rate of 99.5 % achieved in mere 30 min. Besides, the 0.5Co-N-C/g-CN plate also demonstrated an outstanding photocatalytic CO2 conversion rate of 33.7 μmol g−1cat h−1 within 4 h, which was more than 3.4-fold that of g-CN (9.9 μmol g−1cat h−1). Experiments demonstrated that the surface-constructed Co-N-C enhanced the visible light-harvesting and the separation of photo-induced charge carriers, boosting the optical property. Moreover, the density functionalized theory (DFT) calculations verified that the Co-N-C cocatalyst optimized O2 adsorption for the generation of superoxide radicals (·O-2), accelerating the photocatalytic RhB removal. Meanwhile, the Co-N-C was advantageous for the adsorption and activation of CO2, facilitating the photocatalytic CO2 conversion. This study provides a perspective on the surface engineering of g-CN toward enhanced photocatalytic performance.

The insertion of thiazolo[5,4-d]thiazole unit in covalent triazine framework for boosting the photocatalytic capacities in both selective aerobic oxidation of sulfides and amines

Recently, covalent triazine frameworks (CTFs) have realized versatile applications in the field of photocatalysis. Herein, two CTFs photocatalysts were designed and synthesized with or without thiazolo[5,4-d]thiazole (TzTz), an electron deficient unit, to highlight the introduction of an additional acceptor unit on the photocatalytic aerobic oxidation reaction of triazine based CTFs. Specifically, CTF-TZDA was prepared by a condensation reaction between terephthalimidamide and 4,4′-(thiazolo[5,4-d]thiazole-2,5-diyl) dibenzaldehyde (TzTz aldehyde), and similarly, CTF-FPBA was prepared between terephthalimidamide and [1,1′-biphenyl]-4,4′-dicarbaldehyde. CTF-TZDA showed high photocatalytic activities towards aerobic oxidation of both benzyl sulfides and benzyl amines to benzyl sulfoxides and benzyl imines, respectively, and the reaction was powered by blue light. A wide range of substrates can be aerobically oxidized with high yield (about 99%) and high selectivity over CTF-TZDA photocatalyst. The insertion of the TzTz unit lowered that band gap, accelerated the delocalization of π electrons, and elevated the LUMO levels of CTF-TZDA, which are beneficial to extend the light absorption range, and to promote the separation and transfer of photo-induced charge carriers. This work indicates that the insertion of an additional electron deficient unit rich in heteroatoms is considered as a feasible approach towards enhancing the photocatalytic activity of CTFs.

Photocatalytic N-formylation of amines with CO2 over Pt-Bi bimetallic decorated CeO2−x

N-formylation of amines with CO2 is a promising approach to high-efficient utilization of CO2 as C1 feedstock, while conventional thermocatalytic processes suffer from harsh reaction condition and intense energy consumption. In this work, photocatalytic N-formylation of amines with CO2 is achieved at room temperature over Pt-Bi/CeO2−x composite catalyst. The Pt-Bi bimetallic sites increase the concentration of surface oxygen vacancies. Furthermore, the synergistic effects of Pt and Bi improve the light absorption capacity, reduce the band gap energy of the photocatalyst and promote the separation of photoinduced charge carriers. Using PhSiH3 as the reducing agent, the conversion of N-methylaniline reaches 100 % after 3 h irradiation in N, N-dimethylformamide solvent with a N-methylformanilide selectivity of 90.8 %. The composite photocatalyst shows promising cycling stability and universality.

Carbon cloth supported black phosphorus-FeMoO4 composites for peroxymonosulfate-assisted photoelectrocatalytic degradation of tetracycline hydrochloride

This research utilized the solvothermal technique to prepare carbon cloth supported black phosphorus-FeMoO4 (CC-BP-FMO) composites, which were used for the degradation of tetracycline hydrochloride (TC-HCl) through the peroxymonosulfate (PMS)-assisted photoelectrocatalysis (PEC) route. Several characterization techniques were employed to systematically examine the morphology, elemental composition, crystal and molecule structures, magnetism properties, bonding states, energy band structure, separation efficiency of photo-induced carriers, electrochemical behaviors, reactive species, and intermediate products of TC-HCl degradation. The experimental results demonstrated that the performance of PMS-assisted PEC TC-HCl degradation by the CC-BP-FMO composites was significantly improved in comparison with photocatalysis, electrocatalysis, PMS activation, and PEC. The CC-BP-FMO composites with more exposed BP-FMO catalysts exhibited the ability to be reused for PMS-assisted PEC degradation of TC-HCl, with a large k value of 0.21 min−1 and a high degradation rate of 97% after the fourth cycle. The remarkable PMS-assisted PEC property of the CC-BP-FMO composites was mainly attributed to the swift separation of photo-induced charge carriers, which hastened the creation of reactive radicals. Five possible catalytic reaction pathways existed in the CC-BP-FMO composites towards TC-HCl degradation under the PMS-assisted PEC condition. Importantly, the photo-generated electrons and [Formula: see text] radicals were advantageous for the redox reaction of Fe+2/Fe+3 and Mo+4/Mo+6. The oxygen vacancies caused by P and Mo in the BP-FMO heterojunction could suppress the carrier recombination. The degradation of TC-HCl involved the participation of oxygen vacancy, [Formula: see text], [Formula: see text], and ∙OH radicals, and 1O2 nonradicals. The CC-BP-FMO composites have the potential application for treating wastewater containing organic pollutants.

Synthesis of Au‐decorated WO3 nanoplates for simultaneous oxidation of RhB and reduction of Cr(VI) under visible light irradiation

AbstractTungsten oxide (WO3) nanoplates were synthesized by a simple chemical precipitation technique. These nanoplates were decorated by Au nanoparticles via photoreduction route. The obtained samples were characterized by field emission scanning electron microscopy, X‐ray diffractometry and UV–vis diffuse reflectance spectroscopy to investigate their morphological, structural and optical properties. The SEM images show the plate morphology with the size in the range of 50–150 nm, their thickness ≈10 nm; spherical‐like Au nanoparticles ≈20 nm were attached to the surface of the WO3 plates. These materials were applied for the simultaneous photocatalytic degradation of Rhodamine B (RhB) and Cr(VI) under visible light. Due to the efficient separation of photoinduced charge carriers and the enhanced visible light absorption ability, the photocatalytic performance of Au‐decorated WO3 nanoplates was higher. The main active species responsible for the photodegradation reactions were identified by different scavengers and a photocatalytic mechanism was proposed. This work represents that WO3 nanoplates are a promising candidate for the degradation of organic and inorganic pollutants from the industrial wastewater under sun light exposure.

COF-Based Photocatalysts for Enhanced Synthesis of Hydrogen Peroxide.

Covalent Organic Frameworks (COFs), with their intrinsic structural regularity and modifiable chemical functionality, have burgeoned as a pivotal material in the realm of photocatalytic hydrogen peroxide (H2O2) synthesis. This article reviews the recent advancements and multifaceted approaches employed in using the unique properties of COFs for high-efficient photocatalytic H2O2 production. We first introduced COFs and their advantages in the photocatalytic synthesis of H2O2. Subsequently, we spotlight the principles and evaluation of photocatalytic H2O2 generation, followed by various strategies for the incorporation of active sites aiming to optimize the separation and transfer of photoinduced charge carriers. Finally, we explore the challenges and future prospects, emphasizing the necessity for a deeper mechanistic understanding and the development of scalable and economically viable COF-based photocatalysts for sustainable H2O2 production.

Interface-engineered dual Z-scheme of BiVO4/NH2-MIL-125(Ti)/POF photoanode with enhanced photoelectrochemical performance

The key factors that restrain the decomposition activity of photoelectrocatalysis (PEC) are poor redox ability and low charge separation rate. In this work, the dual Z-scheme BiVO4/NH2-MIL-125(Ti)/POF (BiVO4/NM125(Ti)/POF) heterojunctions were successfully established for visible-light driven PEC degradation of phenol. As expected, the optimum BiVO4/NM125(Ti)/POF photoanode exhibited outstanding PEC performance with near-total degradation of phenol within 2 h of illumination. The evaluated activity was assigned to high charge transfer rate and dual Z-scheme heterostructures with double electron transport channels. The fabrication of dual Z-scheme heterojunctions improved a more efficient separation of photo-induced charge carriers while holding a higher redox ability to generate more reactive oxygen species (ROS) such as O2•− and •OH to decompose organic pollutants. In addition, excellent chemical stability and recyclability were also achieved after five times cycles, and the degradation pathway of phenol was also put forward. Finally, the quantitative structure-activity relationship (QSAR) was applied to forecast phenol and its degradation products toxicity. This research gives novel insights into establishing highly effective photoanode with promising applications for organic contaminants degradation, and offers in-depth understanding of charge separation and migration in PEC process.

Highly efficient photocatalytic removal of antineoplastic drug and selective fluorescence detection of organophosphate pesticide employing NiFe2O4 modified 2D g-C3N4 heterostructures

With the goal to detect, quantify and remove virulent toxins for water decontamination, a dual functional platform based on nickel ferrite (NF) modified magnetically retrievable 2D metal free g-Carbon Nitride (CN), with varied ratios of NF, was fabricated via simple sonication-calcination route. The % degradation of antineoplastic drug, doxorubicin (DXR) were obtained to be 69.8 %, 49.1 %, 71.1 %, 85.4 %, 94.2 %, 88.5 % and 81.7 % for CN, NF, 2-CNNF, 4-CNNF, 6-CNNF, 8-CNNF and 10-CNNF, respectively with corresponding rate constant values of 0.069, 0.047, 0.075, 0.100, 0.148, 0.113 and 0.078 min−1. CNNF heterostructure displayed outstanding photocatalytic performance with 6-CNNF heterostructure displaying highest rate kinetics with rate constant value 2.2 and 3.2 times greater than pure CN and NF, respectively. The charge transfer occurring in CNNF heterostructure followed direct Z-scheme mechanistic pathway, which proffers two advantages of high photoinduced charge carriers separation and optimized redox capacity of binary system. UV–vis DRS, XPS and PL results supported the proposed mechanism. Radical scavenging experiments further validated the role of •O2−, h+ and HO• radicals in degrading target pollutant. Moreover, the fabricated material was efficiently employed as selective and sensitive sensor for fluorescence detection of pesticide, chlorpyrifos (CPF) and DXR with respective LOD values of 4.1 µM in the range of 5 µM to 100 µM and 1.6 µM in the range of 0.1 µM to 40 µM. Real world applicability was established by monitoring CPF and DXR in real water samples. This study presents the designing of multi-functional platform, exhibiting excellent optical as well as physical characteristics, for monitoring and obliteration of noxious pollutants in aqueous environment.

Ni(OH)2 Nanosheet as an Efficient Cocatalyst for Improved Photocatalytic Hydrogen Evolution over Cd0.9Zn0.1S Nanorods under Visible Light.

Loading cocatalysts to promote spatial charge separation has been confirmed as an effective method for improving photocatalytic hydrogen production. This article reports that the synthesis of Ni(OH)2/Cd0.9Zn0.1S nanorod photocatalyst is suitable for photocatalytic H2 generation under visible light. It can be proven that the binary photocatalyst exhibits a one-dimensional nanorod morphological structure. Ni(OH)2 nanosheets occupy the top area of Cd0.9Zn0.1S nanorods. The photocatalytic H2 production rate can reach 132.93 mmol·h-1·g-1, which corresponds to an apparent quantum efficiency of up to 76.5% at a wavelength of 460 nm. In addition, the Ni(OH)2 nanosheet can aggregate the light-incited electrons of Cd0.9Zn0.1S, inhibiting the confluence of electrons and holes. The detailed analysis of its mechanism through characterization methods such as photoluminescence and electrochemical measurement shows that the significant improvement in photocatalytic performance derives from the effective spatial separation of photo-induced charge carriers. Therefore, this synthesis strategy of one-dimensional materials may bring new prospects for more efficient, stable, and sustainable photocatalysis for water splitting.

Novel Ag-Bridged Z-Scheme CdS/Ag/Bi2WO6 Heterojunction: Excellent Photocatalytic Performance and Insight into the Underlying Mechanism

The construction of semiconductor heterojunction photocatalysts that improve the separation and transfer of photoinduced charge carriers is an effective and widely employed strategy to boost photocatalytic performance. Herein, we have successfully constructed a CdS/Ag/Bi2WO6 Z-scheme heterojunction with an Ag-bridge as an effective charge transfer channel by a facile process. The heterostructure consists of both CdS and Ag nanoparticles anchored on the surface of Bi2WO6 nanosheets. The photocatalytic efficiency of the CdS/Ag/Bi2WO6 system was studied by the decontamination of tetracycline (TC) and Rhodamine B (RhB) under visible light irradiation (λ ≥ 420). The results exhibited that CdS/Ag/Bi2WO6 shows markedly higher photocatalytic performance than that of CdS, Bi2WO6, Ag/Bi2WO6, and CdS/Bi2WO6. The trapping experiment results verified that the •O2− and h+ radicals are the key active species. The results of photoluminescence spectral analysis and photocurrent responses indicated that the CdS/Ag/Bi2WO6 heterojunctions exhibit exceptional efficiency in separating and transferring photoinduced electron−hole pairs. Based on a series of characterization results, the boosted photocatalytic activity of the CdS/Ag/Bi2WO6 system is mostly due to the successful formation of the Ag-bridged Z-scheme heterojunction; these can not only inhibit the recombination rate of photoinduced charge carriers but also possess a splendid redox capacity. The work provides a way for designing a Z-scheme photocatalytic system based on Ag-bridged for boosting photocatalytic performance.

Construction of a g-C3N4/Bi(OH)3 Heterojunction for the Enhancement of Visible Light Photocatalytic Antibacterial Activity.

Photocatalytic technology has been recently conducted to remove microbial contamination due to its unique features of nontoxic by-products, low cost, negligible microbial resistance and broad-spectrum elimination capacity. Herein, a novel two dimensional (2D) g-C3N4/Bi(OH)3 (CNB) heterojunction was fabricated byincorporating Bi(OH)3 (BOH) nanoparticles with g-C3N4 (CN) nanosheets. This CNB heterojunction exhibited high photocatalytic antibacterial efficiency (99.3%) against Escherichia coli (E. coli) under visible light irradiation, which was 4.3 and 3.4 times that of BOH (23.0%) and CN (28.0%), respectively. The increase in specific surface area, ultra-thin layered structure, construction of a heterojunction and enhancement of visible light absorption were conducive to facilitating the separation and transfer of photoinduced charge carriers. Live/dead cell staining, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) assays and scanning electron microscopy (SEM) have been implemented to investigate the damage to the cell membrane and the leakage of the intracellular protein in the photocatalytic antibacterial process. The e-, h+ and O2•- were the active species involved in this process. This study proposed an appropriate photocatalyst for efficient treatment of bacterial contamination.

Graphite/carbon-doped TiO2 nanocomposite synthesized by ultrasound for the degradation of diclofenac.

Graphite/C-doped TiO2 nanocomposite was synthesized at room temperature using a simple, impressive, and indirect sonication (20kHz) by the cup horn system. Tetrabutyltitanate as the precursor of titanium and graphite (G) as the carbon source was used in the preparation of nanocomposite as a photocatalyst. The molar ratio of G/TiO2 as a key parameter was investigated in the synthesis of G/C-doped TiO2. The obtained materials were widely characterized using XRD, SEM, TEM, FTIR, XPS, and UV-Vis diffuse reflectance techniques. The UV-Vis diffuse reflectance spectroscopy results showed that the edge of light absorption of nanocomposite was distinctly red-shifted to the visible area via carbon doping. The XPS outcomes acknowledged the existence of the C, Ti, and O in the photocatalyst. The composite showed an enhancement in the dissociation efficiency of photoinduced charge carriers through the doping process. The photocatalytic activity of the synthesized nanocomposite was checked with diclofenac (DCF) as a pharmaceutical contaminant. The results displayed that G/C-doped TiO2 represented better photocatalytic performance for DCF than TiO2. This was due to the excellent crystallization, intense absorption of visible light, and the impressive separation of photoinduced charge carriers. Various active species such as •OH, •O2¯, h+, and H2O2 play a role in the degradation of DFC. Therefore, different scavengers were used and the role of each one in degradation was investigated. According to the obtained results, •O2¯ radical showed a major role in the photocatalytic process. This work not only proposes a deep insight into the photosensitization-like mechanism by using G-based materials but also develops new photocatalysts for the removal of emerging organic pollutants from waters using sunlight as available cheap energy.

TiO2 nanorod arrays/Ti3C2T x MXene nanosheet composites with efficient photocatalytic activity

Semiconductor photocatalysis holds significant promise in addressing both environmental and energy challenges. However, a major hurdle in photocatalytic processes remains the efficient separation of photoinduced charge carriers. In this study, TiO2 nanorod arrays were employed by glancing angle deposition technique, onto which Ti3C2T x MXene was deposited through a spin-coating process. This hybrid approach aims to amplify the photocatalytic efficacy of TiO2 nanorod arrays. Through photocurrent efficiency characterization testing, an optimal loading of TiO2/Ti3C2T x composites is identified. Remarkably, this composite exhibits a 40% increase in photocurrent density in comparison to pristine TiO2. This enhancement is attributed to the exceptional electrical conductivity and expansive specific surface area inherent to Ti3C2T x MXene. These attributes facilitate swift transport of photoinduced electrons, consequently refining the separation and migration of electron–hole pairs. The synergistic TiO2/Ti3C2T x composite showcases its potential across various domains including photoelectrochemical water splitting and diverse photocatalytic devices. As such, this composite material stands as a novel and promising entity for advancing photocatalytic applications. This study can offer an innovative approach for designing simple and efficient photocatalytic materials composed of MXene co-catalysts and TiO2 for efficient water electrolysis on semiconductors.

Removal of organic amino derivatives from wastewater by using fluorescent nitrogen-doped GQDs under visible light and fluorescence application under ultra violet light

Photocatalysis is one of the most popular organic waste degradation treatments because it can result in the total decomposition of organic pollutants under visible light illumination. Here, we present a metal-free visible-light active catalyst for the effective decomposition of organic aromatic amino derivatives Methylene blue (MB) and Rhodamine B (RB) as model-contaminated dye molecules. Through a one-pot hydrothermal process, blue colour emissive nitrogen-doped graphene quantum dots (N-GQDs) were synthesized from urea and malic acid. The physicochemical characteristic techniques were used to analyze the surface morphology, elemental analysis, surface functional groups, absorption, emission, and band gap of prepared N-GQDs. The effective light absorption properties, transfer of electrons, separation of photoinduced charge carriers, and excellent stability with a band gap of 2.69 eV of synthesized N-GQDs have enabled the degradation of Rh B and MB up to 90 % and 86 % respectively, within 120 min of visible light irradiation. Based on extensive active species trapping experiments, a probable photocatalytic dye degradation mechanism is proposed. These N-GQDs can also be used to make fluorescent ink for imaging and security purposes.

Load transfer engineering via synergy of BiOI heterojunction with Ag and loading cocatalyst of La2O2CO3 in photoelectrochemical water splitting

Photoelectrochemical water splitting of bismuth oxyiodide, BiOI is of special interest for solar energy utilization. Herein, a novel photoanode designed by compositing BiOI with Ag and loading lanthanum oxy-carbonate, La2O2CO3 as a cocatalyst for oxygen evolution reaction. This design not only decreases the onset potential besides increases the photocurrent and stability. The Ag–BiOI photoanode exhibits an enhancement of 2.5 fold in the photocurrent density compared to BiOI. The maximum photocurrent density of the Ag–BiOI photoanode is achieved for the Ag amount of 1.2 %. The photoelectrocatalytic performance of Ag–BiOI is outstandingly further enhanced after loading the La2O2CO3 layer. The photocurrent density of 0.17 mA cm−2 is attained for Ag–BiOI/La2O2CO3 photoanode with respect to BiOI (0.06 mA cm−2) at 1.23 V vs RHE indicating its high capability for photoelectrochemical water splitting. The photo-potential of Ag–BiOI/La2O2CO3 photoanode (632 mV) is 6.9 and 2.5 times more than BiOI and Ag–BiOI, respectively resulting in the highest degree of band bending and the excellent trapping capability for electrons which leads to the enhancement in the separation and transfer of photo-induced charge carriers. Ag–BiOI/La2O2CO3 photoanode indicates a smaller arc radius in the Nyquist plot compared to those of BiOI, Ag–BiOI, and BiOI/La2O2CO3 photoanodes.

Tailored engineering of rod-shaped core@shell ZnO@CeO2 nanostructures as an optical stimuli-responsive in sunscreen cream

The catalytic efficiency of the materials can be boosted with the selective designing (nanostructures) including the core@shell which aids in attaining the separation of photoinduced charge carriers. However, to effectively separate the carriers and reduce the rate of recombination, tuning the thickness of the shell wall is a vital one. The one-dimensional (1D) rod-like shell wall-controlled ZnO@CeO2 core@shell structures were successfully prepared via co-precipitation and hydrothermal methods using the hexamethylenetetramine (HMTA) as a reagent. The CeO2 shell wall thickness was fine-tuned between 15 and 70 nm with a variation in the concentration of HMTA reagent. The results revealed that the concentration of HMTA played a significant role in the formation of ZnO@CeO2 core@shell structures and in tuning their thickness. The FE-SEM images evidenced the core-shell structures formation with the specific thickness and uniformity. The HR-TEM images confirmed the homogeneity and regular form of the shell thickness. The unit cell and crystallite size were identified from the XRD analysis. The constructed core-shell structures were further employed in the formula of the prototypes of sunscreen and their photoprotective performance was analyzed in the view to cut the solar light irradiation in a new sunscreen formulation. The developed core-shell ZnO@CeO2 structures showed the excellent optical absorption in both the UV as well as visible regions.

Construction of Z-scheme AgCl/BiOCl heterojunction with oxygen vacancies for improved pollutant degradation and bacterial inactivation.

A facile Z-scheme AgCl/BiOCl heterojunction photocatalyst with oxygen vacancies was fabricated by a water-bath method. The structural, morphological, optical and electronic properties of as-synthesized samples were systematically characterized. The oxygen vacancies were confirmed by EPR, which could optimize the band-gap of the AgCl/BiOCl heterojunction and improve the photo-induced electron transfer. The optimized AgCl/BiOCl heterojunction showed excellent photocatalytic degradation efficiency (82%) for tetracycline (TC). Simultaneously, E. coli was completely inactivated within 60 min due to the AgCl/BiOCl heterojunction. The elevated catalytic activity of the optimal AgCl/BiOCl heterojunction was ascribed to the synergistic effect of the enhanced light absorption and effective photoinduced charge carrier separation and transfer. Moreover, the degradation efficiency of the AgCl/BiOCl heterojunction towards ofloxacin, norfloxacin and Lanasol Red 5B was 73%, 74% and 96%, respectively. The experimental factors for the degradation efficiency of TC were also studied. Furthermore, active species trapping experiments indicated that superoxide radicals (˙O2-) were the main reactive species, and the Z-scheme charge transfer mechanism helped to improve the photocatalytic activity.

Nitrogen-doped Bi2O2CO3 nanoplates embedded with surface oxygen vacancies for augmented photocatalytic degradation of levofloxacin

Herein, a series of two-dimensional nitrogen-doped Bi2O2CO3 nanoplates embedded with oxygen vacancies (OVs) are synthesized via a bottom-up self-assembly from one-step hydrolysis. They can serve as efficient photocatalysts that allow a degradation ratio of levofloxacin (LEV) up to 94.4 % in 50 min under simulated sunlight, which is 2.5 times over undoped Bi2O2CO3. Incorporation of N atoms into the Bi2O2CO3 lattice not only extends the light absorption range for more effective utilization of solar light, but also narrows the band gap and increases the OVs concentration. Therefore, the separation of photo-induced charge-carriers is promoted, and further, the production of active species, mainly holes (h+) and superoxide radicals (•O2−), is accelerated.

Well-Separated Photoinduced Charge Carriers on Hydrogen Production Using NiS2/TiO2 Nanocomposites.

Photocatalytic hydrogen production is a sustainable and greenhouse-gas-free method that requires an efficient and abundant photocatalyst, which minimizes energy consumption. Currently, interests in transition metal chalcogenide materials have been utilized in different applications due to their quantum confinement effect and low band gaps. In this study, different wt % of NiS2-embedded TiO2 nanocomposites were synthesized by a facile hydrothermal method and utilized for photocatalytic hydrogen production under extended solar irradiation. Among the materials studied, the highest amount (4.185 mmol g-1) of hydrogen production was observed with 15 wt % of the NiS2/TiO2 nanocomposite. The highest photocatalytic activity may be due to the well separation of photoinduced charge carriers on the catalyst, which was confirmed by the electrochemical studies. Thus, we believe that these photocatalysts are promising candidates for future applications.